Reversible inertia transmission



Feb. Il, 1930. R J. A. MALM 1,746,545

` REVERSIBLE INERTIA TRANSMISSION Filed Feb. 14, 1927 2 Sheets-Sheetl 27 ff 33 L 3/ Jan J4. /(a im.

Patented Feb.. 11, 1930 JOHN A. MAL1VI,` OF DENVER, COLORADO .VREVELSIBLE INERTA TRANSMISSION A Application led February 14, 1927. Serial No. 167,975.

This invention relates to improvements in variable speed reversible inertia power trans'- mission devices.

It is often desirable to transmit` power 5 from one shaft to another in such a manner that the driving shaft may rotate at a con` stant speed .and deliver a constant torque to a driven shaft which supplies power to a variable speed device and whose speed of rotation is an inverse function of the torque l which it must produce. Such transmission devices are'useful in many places, but more especially in connection with automobiles which must traverse roads having a great variety of grades and which carry diierent loads at different times.

It is customary to provide automobiles with transmission gear sets that are manually shiftable and by means of which the trans- 20 mission ratio between the driving and the driven shaft can be changed whenever necessary. Such gear sets are provided with means for effecting only a very few changes and therefore do not .permit the motor to run at the most eiicient 'speed at all times and besides this, such gear sets must be constantly shifted.

It is the object of this invention to produce a transmission mechanism that willau- 33 tomatically va `y the gear ratio between the driving and tl e driven shafts so that the speed of the di'iven shaft multiplied by the torque which it delivers will always be equal to the speed of the driving shaft multiplied by its torque minus the loss in the transmisy sion device and which, at the same time, will rotate the driven shaft at the maximum speed possible under the conditions. v

It is a further object ofthis invention to 43 produce a transmission device that permits the relative direction of rotation of the driving and the driven shaft to be reversed when neccssar v The above and other objects that may be- 45 come apparent as the description proceeds are attained by a mechanism, which, briefly described, consists of two aligned, relatively rotatablcshafts mounted for rotation and held against relative longitudinal movement. L A flywheel carried by said shafts in such a lmanner that itinay rotate'and move longi- -tudinally with respect to bothof the shafts and means for causing the flywheel to reciprocate when the shafts rotate relative to each other, together with a brake mechanism yby 55 means of which the flywheel' may be retarded so as to reverse the relative rotation of the shafts.

In order more full to describe my apparatus and its operation, reference will now be hadto the accompanying drawings in which it has been illustrated, and in which Fig. 1 is a longitudinal diametrical section of my improved reversible inertia transmission; 4

Fig. 2 is a section taken on line 2 2, Fig. l, the flywheel being shown partially broken away;

Fig. 3 is a section taken on line 3-3,

Fig. 1;

Fig. 4 is a diagrammatic representation of the cams and interconnecting rollers and is intended to illustrate the operation; i

Fig.` 5 is similar to Fig. 4 and shows the shafts rotating reversely; Fig. 6 is a longitudinal section similar to that shown in Fig. 1,'but showing a modified construction: and

Fig. 7 is a section taken on line 7 `,7 Fig. 6.

For the purpose of illustrating and-describing this invention, the drivinf` shaft 1 and the driven shaft 2 have been shown as journalled in bearings 3 and 4, which are formed in the upper ends of the uplrights 5 and 6 that project upwardly from t e base 7. ln this description shaft 1"will be considered to be the driving shaft and 2 the driven shaft, but I want it distinctly understood that this may be reversed and shaft 2 be the driving shaft.

Shaft 1 is provided with an axial opening 90 8 and has a cylindrical section 9 of somewhat larger diameter than the adjacent portions 10 and 11, so as to form two shoulders 12 and 13. A cam member 14 is secured to the part 11 by means of ascrew 15. Shaft 2 is also pro- 95 vided with a section 16 of larger diameter than the shaft 2 and an extension 17 which is journalled in the opening 8. The shoulder between sections 16 and 17 engages the end oi.'

the hollow part 11 and the shoulder between m0 i 12 and 2 abuts the end of the's'leeve 18. The

other end of sleeve18 abuts the end of the bearing 4.v Shoulder` 12 and sleeve 18 hold the shafts 1 and v2 against relative longitudia smaller or'greater number of nodes. The

sleeve 18 is provided with a plurality of splines 21 which cooperate withcorresponding grooves in the hub 22, which is integral with the, sleeve 23. A flange 24 extends ral dially outwardly from the sleeve 23 inthe plane of the hub and is provided with a plu` rality of openings for the reception of the bolts 25 by means of which the sleeve,23 is secured in place in the cylindrical vchamber 26 of the fly-wheel 27. A wheel 28 is secured to the end of sleeve 18 by means of screws 29 and has a cylindrical surface 30 with which the. brake band 31 cooperates. I have gnot shown any means for contracting the brake band as I contemplate employing any of the old and well-known means for this purpose. f

The flywheel 27 has an axial opening of the pro r size to lit slidably on the part 9 of shafte 1. l c c Sleeve 23 isiprovided-with three pairs of steel pins 33, which, in the example shown, are spaced 120 degrees apart, 'about the axis of the cylinder, and are so spaced longitudinally that they engage corresponding portions of the cam grooves 20. As explained above,

the cams and the cam ooves are identical so that if we suppose t at. the cams are arranged with the corresponding nodes in the sam'diametrical plane 'andleld against relative rotation that the flywheel ma be rotated about the common axis of the s afts. The pin 33 will follow the grooves'and therefore the flywheel will be forced to reciprocate as the pins ass from one node to the other. The pins 33 ave been shown as held inplace by means ofarod 34. f X p Let us now assume a case in which shaft 1 is rotated by some suitable motor and that shaft 2 is free to rotate. If we increase the angular speed of shaft 1 very slowly, the flywheel 27, as well as shaft 2, will be made to rotate at the same angular speed and the whole assembly will therefore rotate as a unit. 7

LetA us now assume that a load is gradually applied to shaft 2, which tends to stop its rotation. Shaft 2 will begin to lag behind shaft 1 and there will be relative rotation between cams 14 and 19. As soon as the cams begin to rotate relative to each other, the flywheel will beginto reciprocate because the v,distance between the two pins 3 of each pairis fixed.

This also necessitates a.relative rotation of the flywheel about shaft 1, for otherwise there can be no reciprocation. If we clamp the free to rotate as well to rotate,

shaft 2 against rotation, but` leave the flywheel as to reciprocate, the flywheel willl make one-half of a revolution to each revolution of shaft 1, because and since there are six 'nodesthe flywheel must rotate 60 degrees in passing from one n ode on the stationary cam 19 to the next node or from node X to node Y in F ig; 4 and during this movement of the flywheel cam 14. must' rotate through 120 degrees so thatnode a will lie in the same diametrical plane as node Y. Since the cam 19 is Inot rotating,l in the case under consideration, the flywheel 27 will reciprocate three times during each revolution of the drive shaft. If shaft 2- is permitted the flywheel will rotate at a ,smaller speed relative to shaft 1 than when shaft 2 is held against' rotation and at the same time it will reciprocateat a lower rate.

vFrom the abovel it will be 'observed that when the shaft 2 isfree to rotate, the flywheel will rotate at the same speed as shaft 1 and will not ,reciprocate and that when shaft 2' is held against rotation, the flywheel will rotate at one-half the speed of shaft 1 and reciprocate at the maximum rate. Since it re uires considerable 'force to reciprocate the ywheel, it is evident that this force must be produced by the interaction between the pins 33 and the walls of the cam groove 20 incam 19 and thatthis forceis a direct functionofthe rate at which shaft 2 lags with respect to shaft 1, for it has been shown that when the lag is zero, the flywheel does not reciprocate and that when the lag is the maximum vthe rate of reciprocations are the maximum. Since inertia and momentum vary with the uare of the velocity, it is evident that the orce Imust be quadrupled in order to double the rate of reciprocation.

' From the-above explanation, it is apparent that if shaft 1 is rotated at a constant speed and shaft 2 is connected with a variable load, it will be rotated at such a s eed that the angular speed multiplied by t e torque will be equal to the power required to reciprocate the rotating flywheel at-the corresponding rate. y

In order to explainv the operation 'in a diffrent way, reference will now be had to Fig. 4 in which it is assumed that cam 14 is rotated in the direction of the arrow by means of a motor. fPins 33 are rigidly connected one to the other as explained above. Shaft 2 is rotatable but subject to considerable friction or to some other load. It is now evident that the side b of the cam groove 20 in cam 14 will engage the pin 33 and subject the latter to a force. v. This force acts perpendicular to the side of the cam groove and can be resolved into two components,

one of which extends parallel with the axis but at a'slowerl speed than shaft 1,

' 35 i this case shafts 1 and 2 will have to rotate ateatro a plane at right angles to the axes and represents the torque. The -Pin 33 in thev cam grooveof cam 19 will now engage the side C with a force that can be resolved into two components, one of which is parallel with the axis of rotation and the other Aof 'which acts 1n a plane perpendicular to the axes and represents the torque which tends to rotate the shaft 2. Since the forces referred to are dependenton themoment of inertia of the flywheel, it is evident that they will vary `directly as the mass andr directly as the square of the velocity or as the square lof the frequency of the reciprocation. After the 'pins l .15 have passed nodes a andy the reactions will be between the pins land sides e and f. If the load increases, the frequency of reciprocation must increase so as to develop the necessary torque and therefore there must be an increase ,in the relative rotation of shafts 1 and 2,

which means that the'rotary speed of shaft 2 will decrease as the load increases. This device therefore functions to automatically change vthe transmission ratio between shafts 1 and 2 in accordance with the load.

This device also possesses the properties of being adapted to vreverse the direction of rotation of shaft 2 without reversing shaft 1. This is accomplished in the following manner.

Let us assume that the parts are rotating in the saine direction, as above described, and that the pins 33l are in the position shown in Fig. 4. As above explained, it is possible to clamp the tlywheel against rotation and in at the same speed but not necessarily in the saine direction). Under normalv operation, the flywheel rotates in the saine direction as shaft 1, but at a lslower angular speed. ln this case the cam 19 is rotated in the saine direction as cani 1d, for reasons explained. If we now apply the brake 31 to the wheel 28, we increase the'torque required to rotate it and therefore the ywheel will lag more with respect to shafty 1 and thereby be forced to .reciprocate at a greater rate. This increase in the rate of reciprocation will force pin 33 against the side g of the cani groove in cain 19 (Fig. 4;) and this force is resolved into two right angular torces, one of which represents a torque tending to rotate the cam 19 in the direction of the arrow in Fig.' 5. Shaft 2 will now be gradually brought to rest and its direction oi rotation reversed. When the brake is released, the rate of reciprocation will be reduced and shaft 2 will again be reciprocated in the same direction as shaft 1. In the above description the cam grooves have been described as being identical in shape and size but this is. not necessary. @ne cam groove may have sin nodes, as shown, and the other one nine., or it may have four nodes. lin the latter case the pins 33 must be placed diametrically so as to coo erate with the lcain groove. In Letters atent 1,525,038 granted to me on February 3, 1925, I have explained in detail the operation of a similardevice having cam members whose cam grooves have different numbers of nodes and will therefore not oder any further explanation than to say that the relative rotation between each cam member and the -flywheel for each reciprocation of the latter varies inversely with the number of nodes.

I also desire to call attention to the fact that power ma be delivered to the wheel 28 instead of to t 'e shaft 1 and transmitted to either one or both of shafts 1 and 2. If shaft 1 is connected with, the machine to be operated, shaft- 2 must be providedlwith a brake mechanism similar to that now shown associated with wheel 28. i

In the above speciication I have referred to the inertia member v27 as a flywheel as it functions by virtue of its inertia to resist sudden changes of speed ordirection of Inovei ment and `I want it understood that this term comprises any shaped member and that I do a round or cylindrical one, although this is the most suitable shape.

operation is identical. In order to reverse the positions'of the pins and cam grooves, however, various changeshave been made in the `construction and these willfnow be described. y

Shaft 1 has secured to its inner end a ring 35 provided with two diametrically opposed pins 36. @hatt 2 has a sectionltia of somewhat larger diaineter'than the shaft and this is provided with a diametrical opening for 'the reception of the pin 37, which is held in place therein by a set screw 38. The cylindrical opening `in the dywheel instead of being ot the same diameter throughout its entire length, has one end of the' same cliameter as the interior of the sleeve 23. A cam ring' 39 is secured tothe vtiywheel'by means of screws d0. Another cam ring d1 is spaced from ring 39 so las to form a cam groove of suiiicient width' to receive the pins 36 and is secured to sleeve 23 by means of screws d2. .it third cam ring 43 is spacedv from ring 411 a distance equal to the diameter of pin 3l and is secured to sleeve 23 by screws ed. By removing the bolts 25 the sleeve 23 and attached rings d1 and d3 may be separated trom the tlywheel which maires screws ft2 and ld accessible.- The cam grooves beu tween rings 33, d1 and 11, d3 are parallel and l lid iat

V not therefore want to be limited thereby to v correspond to the cam grooves 20 in the modification described above. H i

As vthis modified form-operates iin exactly the samel'way as theone that has beende-v l'The cam grooves in scribed above, no attempt will be made to describe the operation an ful-ther.

oth' of the embodiments are parabolic as this gives the smoothest action. Since the cams and pins are all l cont'ained in the chamber.'

' a cam having-a cam enclosed in a chamber in the flywheel, they can be easily lubricated as the oil can be Having thus described the invention'what is claimed as new 1s:

1. A transmisslon device com rising, 1n

combination, two relatively rotata le axially' aligned shafts, a flywheel enclosing the adja` combination, two aligned relatively rotatable shafts, a flywheel enclosing adjacent ends of the shafts, the flywheel 'being movable with respect to both shafts and means Vcomprising oove,and pins operatively associated wit the cam grooves. for connecting each of said shafts with the fiywheel. v f l 4 4. A transmission device comprising, in

. combination, two axially aligned relatively .rotatable shafts, a cam member'secured to eachof the adjacent ends of'said shafts, each -cam member having an endless cam groove extending around it, each of said cam grooves having a plurality of nodes, an inertia member having a central opening adapted to receive and enclose said cams and pins connected with the inertia member and engaging the cam grooves.

5. A transmission device comprising, .in combination, two axially aligned relatively rotatable shafts, cam members secured to the yadjacent ends of said shafts, a cylindrical sleeve enclosing the adjacent ends of said shafts, means for connecting the sleeve with each of said shafts, said means comprising a cam having an endless cam groove anda pin havin one end in said groove.

6.v n inertia transmission device, comprising, in combination, two axially aligned relatively rotatable shafts, an inertia member rotatablycarried b said shafts and means for interconnecting t e shafts and inertia member so that the latter will be forced to revciprocate whenever it rotates relative to either oneof the shafts. f'

7. An inertia-transmission device, comprising, in combination, two axiall aligned, relatively rotatable shafts, means or holding the shafts in axial alignment, a brake drum ro- Y tatably connected with one of said shafts, said drum having an elongated hub provided on its outer surface with a plurality of splines, an inertia member having an axial chamber enclosing ad'acent ends of said shafts, said inertia mem' r having grooves which cooperate with the splines on the hub .of the brakeY drum and means for connecting the inertia member with each of the shafts,l said means comprising a cam having an endless cam groove that is concentric with the axis of the shafts and pins having one end projecting' into said groove. 'l

l 8. A transmission device comprising, in combination, two axially'aligned, relatively rotatable shafts, a cam member nonrotatably associated with each shaft, an inertia member and means for connecting the inertia member to the cams in such amanner that it will be reciprocated whenever the cam members'are rotated relative to each other.

9. A transmission device comprising, in combination, two relatively rotatable shafts, an inertia member surrounding adjacent ends of the shafts, means for supporting said memberV so that it may be reciprocated and means for reciprocating said member at a rate that is directly proportional to the rate of relative rotation of the shafts. v

10. A transmission device com rising, in combination, two relatively rotatable axially aligned shafts, an inertia member surrounding adjacent ends of said shafts, a cam meinber nonrotatably secured to each of saidy shafts, the inertia member enclosing said cams, means for interconnecting the inertia member with each of the cams so that the inertia member will be reciprocated when the cams rotate relative to each other and means for applying friction to the inerta member so as to retard itsrotation.

In testimony whereof I aflix my signature.

' JOHN A. MALM.

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